Sleep apnea is a common sleeping disorder characterized by a brief interruption of breathing during a sleeping period. These episodes can last up to 10 seconds and occur repeatedly throughout the sleeping period. People with sleep apnea will partially awaken as they struggle to breathe and in the morning they will not be aware of the disturbance in their sleep. This condition affects over 12 million people. Not treating this condition may result in high blood pressure and a decrease in hemoglobin oxygen level. Untreated cases of sleep apnea can cause a person to fall asleep during normal activities such as working at a computer, talking on the phone or driving a car (which can be fatal).
There are three types of sleep apnea: (1) Obstructive Sleep Apnea (OSA), which is the most common, caused by relaxation of the soft tissue in the back of the throat that blocks the air passage; (2) Central Sleep Apnea (CSA) caused by irregularities in the brain's normal signals to breathe; and (3) Mixed Sleep Apnea (MSA), which is a combination of these two.
One of the methods applied to treat sleep apnea is to use a continuous positive airway pressure (C-Pap) machine or a bi-level positive airway pressure (Bi-Pap) machine. This equipment consists of a face mask which covers the nose and/or mouth area. The face mask is attached to a tube and a motor with a compressor that blows pressurized air into the mask and through the patient's airway to keep it open. This machine is designed to assure that the patient is able to experience a deep and adequate sleeping period. During the use of the C-Pap machine, when the A.C. power source is interrupted for a few seconds, the unit goes into a fault alarm that causes the machine to stop providing pressurized air flow. Because airflow has stopped and the patient's air passage is covered with a face mask, this has the unfortunate consequence of suffocating the patient while he or she is asleep. When there is a prolonged A.C. power outage the machine simply turns off and the same result is obtained where a suffocating period commences.
Present day solutions to this problem suggest a rechargeable battery connected to the machine by means of a D.C. connector. The respiratory machine is sensitive to the D.C. voltage it uses and its stability. Commonly the input voltage range is 11-14 volts D.C. Once the battery is depleted the user must then recharge the rechargeable battery with a battery charger. The most common problem is not charging the battery when required, which deteriorates the capacity to store energy. When the battery is over-charged the battery can spill acid and fumes that may cause serious damage to skin, eyes or irritation of the respiratory passage. The charging procedure requires that the D.C. adaptor cable which is connected to the machine be removed while recharging the battery. This avoids high voltage and current to be exposed to the machine during the charging cycle, which may cause damage. However the patient must take caution in not shorting out the D.C. connection cable with the battery terminals which are exposed. A patient must also take caution that no metal objects short out the battery terminals damaging the battery as well as causing danger to the patient due to spark and acid contents. Patient must store the charger and place the battery in a dry safe area and periodically recharge the battery to maintain its capacity to store energy.
One obvious problem with this configuration is the maintenance required to maintain the battery. Another less obvious problem results from the operation of the C-Pap machine. Specifically, upon a momentary loss of power, the C-Pap machine may activate an alarm to alert the patient of the condition. One example of such a system is shown in U.S. Pat. No. 6,392,555, titled “Medical Equipment Warning Device,” which issued to Most, Jr., on May 21, 2002. It is important that patients being treated for sleep apnea should not be awoken unless absolutely necessary. Waking such a patient upon a momentary lapse of power is counterproductive to treatment.
Hospitals generally have auxiliary power sources that supply electricity if the primary source fails for any reason. Hospital auxiliary power is provided within seconds when there is a power failure. Individual homes generally do not have an auxiliary power source unless it is a backup generator. In the unlikely event of a power failure in a hospital, home care facility or a residence there is an interruption of power to the machine. If an immediate manual reset is not performed the machine will stop operating and the patient will experience a suffocating episode. Once the auxiliary power source is supplying power, it is necessary to manually reset the respiratory machine. A person that depends on a respiratory machine to treat sleep apnea requires a backup device that will assure that his sleep is not interrupted due to a power failure or alarm.